Alternatives to TypeScript enum

Typescript enum이 쓰레기란 말을 어디서 듣고 와서, 대안을 찾아 보았다.

이곳에서 일부 발췌

Object Literals

const DIRECTIONS = {
  UP: "UP",
  DOWN: "DOWN"
} as const;
type DIRECTIONS = typeof DIRECTIONS[keyof typeof DIRECTIONS];

It works!:

const d1: DIRECTIONS = DIRECTIONS.UP; // OK
const d1: DIRECTIONS = "UP";         // OK
const d2: DIRECTIONS = "PLASTICS";  // Error
const d3: DIRECTIONS =  // Autocompletes: "UP", "DOWN"

The solution relies on the following advanced TS features:

• const assertions to not lose the information about the specific strings in the object.
• typeof to get the type of a variable
• keyof to get a union type for the keys of the object.
• union types
• lookup types to index into an object type
• The distributivity of union types: ObjType["A" | "B"] is the same as ObjType["A"] | ObjType["B"]
• the trick that a type aliases and constants live in separate worlds, so can have the same spelling.